Auto merge of #4298 - behnam:ignore, r=alexcrichton
Auto merge of #4298 - behnam:ignore, r=alexcrichton

[src/doc/manifest] Add section on Migrating to `gitignore`-like pattern matching

Tracking issue: https://github.com/rust-lang/cargo/issues/4268

eminence/cargo,tsurai/cargo,rustyhorde/cargo,achanda/cargo,nipunn1313/cargo,nipunn1313/cargo,tsurai/cargo,eminence/cargo,rustyhorde/cargo,eminence/cargo,rust-lang/cargo,rust-lang/cargo,rust-lang/cargo,eminence/cargo,rustyhorde/cargo,achanda/cargo,tshepang/cargo,nipunn1313/cargo,tshepang/cargo,vojtechkral/cargo,vojtechkral/cargo,nipunn1313/cargo,tshepang/cargo,tshepang/cargo,achanda/cargo,tsurai/cargo,achanda/cargo,vojtechkral/cargo,tsurai/cargo,vojtechkral/cargo,tsurai/cargo,rust-lang/cargo,rustyhorde/cargo